Hamilton, U.S. Pat. No. 3,446,856 discloses an alkylation procedure for methylating the ortho position of phenol. This procedure is a vapor phase reaction of a phenol with methanol in the presence of a magnesium oxide catalyst, at a catalyst bed temperature of 475.degree. to 600.degree.C. The service life of the Hamilton catalyst has been relatively short due to the high temperature at which the reaction takes place. It has also been found that the selectivity of the Hamilton catalyst with respect to methanol has been in the range of 40 to 50%. In commonly assigned U.S. patent application Ser. No. 114,698 of Bernardus J. Van Sorge, which is incorporated by reference, there is disclosed a manganese oxide-magnesium oxide catalyst which has extended service life and has a greater degree of selectivity than the Hamilton catalyst. Magnesium oxide catalysts are however subject to carbonization (coking) and eventually these catalysts must be reactivated. The standard procedure for reactivating magnesium oxide catalysts has been based on heating the carbonized catalyst in an atmosphere that contains oxygen. This procedure has partially reactivated the catalyst but not to the extent where the regenerated catalyst was as active as freshly prepared catalyst.
Accordingly, it is a principal object of this invention to provide an improved method of reactivating a magnesium oxide catalyst.
It is also an object of this invention to provide a method for the reactivation of a magnesium oxide catalyst that is capable of restoring the catalytic activity to the level of activity possessed by a freshly prepared catalyst.